.changeable_values
{
  float: left;
  border: 1px solid #999;
  margin: 0 15px 15px 0;
}

.constant_values
{
  border: 1px solid #999;
  margin: 0 15px 15px 0;
}

.extra
{
  float: left;
  border: 1px solid #999;
  margin: 0 15px 15px 0;
}